Home Node B/Home evolved Node B (HNB/HeNB) is a kind of small base station with low power, deployed at home and enterprises. It is capable of providing higher speed for users within a relatively small coverage area, and also capable of solving coverage problem in some spots with poor signal propagation for operators.
FIG. 1 shows a network structure of a Long Term Evolution Advance (LTE-A) system after the HeNB is involved. The HeNB may be connected with a core network directly or via a proxy node, Home evolved Node B Gateway (HeNB GW).
It should be noted that, the HNB/HeNB is a base station supporting a CSG function. The CSG function enables a specific subscribed user to access one or more CSG cells which may provide higher access priority and higher service speed for group members. The CSG function can also implement a special charging policy based on the CSG cell. Each CSG cell has a CSG ID, User Equipment (UE) may obtain the CSG ID and a working mode supported by the cell through system information broadcasted via an air interface.
A cell supporting the CSG function may operate in Closed mode or Hybrid mode. A closed CSG cell only allows users who have subscribed to this CSG ID to access. A Hybrid CSG cell allows access of both subscribed users and non-subscribed users. But it may provide higher access priority and higher service speed for subscribed users.